Image correction apparatus that performs color matching between multiple image pickup apparatuses that take image of display apparatus, image pickup system, control method, and storage medium

Abstract

An image correction apparatus which improves the accuracy of color matching between image pickup apparatuses. The image correction apparatus performs color matching between the image pickup apparatuses using picked-up images generated by displaying a display image on a display screen and causing the plurality of image pickup apparatuses to shoot the display image. In the image correction apparatus, viewing angle correction values for use in correcting viewing angle characteristics resulting from positions of the plurality of image pickup apparatuses with respect to the display screen to a predetermined viewing angle characteristics are stored in memory, corrected images are generated by subjecting the display image in the picked-up images to correction using the viewing angle correction values, and color correction values for use in color matching between the plurality of corrected images are calculated.

What is claimed is: 
     
         1 . An image correction apparatus that performs color matching between a plurality of image pickup apparatuses, the image correction apparatus comprising:
 at least one memory that stores a set of instructions; and   at least one processor that is configured to, based on the instructions, cause the image correction apparatus to:   obtain a plurality of picked-up images generated by the respective plurality of images pickup apparatuses shooting a display image displayed on a display screen of a display unit; and   obtain (i) viewing angle correction values for use in correcting at least one of brightness unevenness or color unevenness that occurs in each of the plurality of picked-up images resulting from different positions of the plurality of image pickup apparatuses relative to the display screen, and (ii) color correction values for use in color matching between the plurality of picked-up images.   
     
     
         2 . The image correction apparatus according to  claim 1 , wherein the viewing angle correction values are used to correct the brightness unevenness that occurs in each of the plurality of picked-up images resulting from the different positions of the plurality of image pickup apparatuses relative to the display screen. 
     
     
         3 . The image correction apparatus according to  claim 1 , wherein the viewing angle correction values are used to correct the color unevenness that occurs in each of the plurality of picked-up images resulting from the different positions of the plurality of image pickup apparatuses relative to the display screen. 
     
     
         4 . The image correction apparatus according to  claim 1 , wherein the viewing angle correction values are used to correct the brightness unevenness and the color unevenness that occurs in each of the plurality of picked-up images resulting from the different positions of the plurality of image pickup apparatuses relative to the display screen. 
     
     
         5 . The image correction apparatus according to  claim 1 , wherein
 obtaining the plurality of picked-up images includes obtaining a plurality of first picked-up images obtained by the respective plurality of images pickup apparatuses shooting a first pattern image displayed on the display screen of the display unit and a plurality of second picked-up images obtained by the respective plurality of images pickup apparatuses shooting a second pattern image displayed on the display screen, and   the viewing angle correction values and the color correction values are obtained based on the plurality of first picked-up images and the plurality of second picked-up images.   
     
     
         6 . The image correction apparatus according to  claim 5 , wherein the viewing angle correction values are obtained based on the plurality of first picked-up images, and the color correction values are obtained based on the plurality of second picked-up images. 
     
     
         7 . The image correction apparatus according to  claim 2 , wherein
 obtaining the plurality of picked-up images includes obtaining a plurality of first picked-up images obtained by the respective plurality of images pickup apparatuses shooting a first pattern image displayed on the display screen of the display unit and a plurality of second picked-up images obtained by the respective plurality of images pickup apparatuses shooting a second pattern image displayed on the display screen, and   the viewing angle correction values are obtained based on the plurality of first picked-up images, and the color correction values are obtained based on the plurality of second picked-up images.   
     
     
         8 . The image correction apparatus according to  claim 5 , wherein the first pattern image is an even image of a specific color, and the second pattern image is a color chart image in which one or more patch images of different colors are arranged. 
     
     
         9 . The image correction apparatus according to  claim 5 , wherein the viewing angle correction values are used to make pixels corresponding to the first patten image in each of the plurality of first picked-up images uniform in at least one of brightness or color. 
     
     
         10 . The image correction apparatus according to  claim 5 , wherein
 an image pickup apparatus having a smallest angle between an optical axis of the image pickup apparatus and normal to the display surface of the display unit among the plurality of image pickup apparatuses is used as a reference image pickup apparatus; and   the viewing angle correction values are used to match distribution characteristics with respect to at least one of brightness or color of pixels corresponding to the first patten image in each of the plurality of first picked-up images with the distribution characteristics of pixels corresponding to the first patten image in the first picked-up image obtained from the reference image pickup apparatus.   
     
     
         11 . The image correction apparatus according to  claim 10 , wherein the color correction values are used to match colors of each of a plurality of corrected images generated from the respective plurality of second picked-up images with colors of a corrected image generated from the second picked-up image obtained from the reference image pickup apparatus. 
     
     
         12 . The image correction apparatus according to  claim 5 , wherein the viewing angle correction values are used to match distribution characteristics with respect to at least one of brightness or color of pixels corresponding to the first patten image in each of the plurality of first picked-up images with the distribution characteristics of pixels corresponding to the first patten image in a picked-up image obtained by shooting the first pattern image in advance from a position at the normal to the display surface of the display unit. 
     
     
         13 . The image correction apparatus according to  claim 1 , wherein the at least one processor is further configured to cause the image correction apparatus to:
 store the at least one of brightness unevenness or color unevenness;   detect angles of optical axises of the plurality of image pickup apparatuses relative to the normal to the display surface of the display unit; and   calculate the viewing angle correction values based on the stored at least one of brightness unevenness or color unevenness corresponding to the detected angles.   
     
     
         14 . The image correction apparatus according to  claim 1 , wherein the position of the display image on the display surface of the display unit is not changed while the display image is shot by the plurality of image pickup apparatuses. 
     
     
         15 . The image correction apparatus according to  claim 1 , wherein the display unit is a display wall comprising a plurality of LED display units. 
     
     
         16 . The image correction apparatus according to  claim 1 , wherein the display unit is a screen on which the display image projected by a projection apparatus is displayed on the display surface. 
     
     
         17 . A control method for an image correction apparatus that performs color matching between a plurality of image pickup apparatuses, the control method comprising:
 obtaining a plurality of picked-up images generated by the respective plurality of images pickup apparatuses shooting a display image displayed on a display screen of a display unit; and   obtaining (i) viewing angle correction values for use in correcting at least one of brightness unevenness or color unevenness that occurs in each of the plurality of picked-up images resulting from different positions of the plurality of image pickup apparatuses relative to the display screen, and (ii) color correction values for use in color matching between the plurality of picked-up images.   
     
     
         18 . A computer-readable non-transitory storage medium storing a computer-executable program for executing a control method for an image correction apparatus that performs color matching between a plurality of image pickup apparatuses, the control method comprising:
 obtaining a plurality of picked-up images generated by the respective plurality of images pickup apparatuses shooting a display image displayed on a display screen of a display unit; and   obtaining (i) viewing angle correction values for use in correcting at least one of brightness unevenness or color unevenness that occurs in each of the plurality of picked-up images resulting from different positions of the plurality of image pickup apparatuses relative to the display screen, and (ii) color correction values for use in color matching between the plurality of picked-up images.